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MANUAL P/N 316005 REV: B
elastic properties of the metal of the diaphragm. For this reason, large pressure excursions, such as occur
when the system is raised to atmospheric pressure, can cause offsets to the pressure reading. The
diaphragm is also extremely sensitive to temperature effects, and although it may be held in a temperature
controlled chamber, this temperature control is never perfect, resulting in further perturbations to the devices
theoretical accuracy. Note that these perturbations are inherent in the capacitance manometer design and
are not a property of the electronic module used to operate the transducer.
Capacitance manometers are capable of exceptional accuracy, and read pressure independent of gas type,
but are also subject to zero-point drift, and must be calibrated at vacuum frequently if high accuracy is to be
obtained. Refer to the manual for your transducer for instructions.
1.7 Calibration
Calibration instructions for each gauge module are contained in the chapter for that module. Convectron
gauge calibration is in section 2.5; thermocouple calibration is in section 3.5; capacitance manometer
calibration is in section 4.5.
1.8 Basic Troubleshooting
1.8.1 Guidelines
Further troubleshooting information is located in the chapters for the specific modules.
The 316 VGC is designed for easy repair by replacement of modules.
If the user elects to perform repairs at the component level, repairs properly made with equivalent electronic
parts and rosin core solder do not represent a violation of the warranty.
Some minor difficulties are user-correctable, and the built-in diagnostic aids described here may be helpful.
Each module has status LEDs which will aid in localizing failures. These are described in the troubleshooting
section of the chapters for each module. Shown in Figure1-7 are those LEDs found on the 316 VGC power
supply board. This is the PC board on the right side (when viewed from the front) of the 316 control unit.
Since the 316 VGC contains static-sensitive electronic parts, the following precautions must be followed
when troubleshooting:
x
Use a grounded, conductive work surface.
x
Use conductive envelopes to store or ship MOS devices or printed circuit boards.
x
Do not operate the 316 VGC with MOS devices removed from the unit.
x
Do not handle MOS devices more than absolutely necessary, and only when wearing a ground
strap.
x
Do not use an ohmmeter for troubleshooting. Rely on voltage measurements.
x
Use grounded-type soldering iron only.
Danger – High Voltage
High Voltages are present within the Controller, capable of causing injury or death. Do not touch
cable connections or circuitry of the power supply module when power is applied.
